1. Field of the Invention
The present invention relates to an automatic seat position adjusting device for an automotive vehicle to adjust a driver's seat position and sitting posture for each of the adjustment directions; a seat front-and-rear direction, a seat up-and-down direction, a seat back tilted angle, a seat back lumbar support angle, a seat cushion titled angle, and a head restraint up-and-down direction.
2. Description of the Prior Art
A conventional motor-powered seat adjustment device has been used for front seats of an automotive vehicle to adjust the seat height, forward-and-backward position, and tilt. On some automotive vehicles, the powered seat adjustment device can adjust a seat back tilted angle, a lumbar support angle, and a head restraint height in addition to the above-described adjustable directions of the seat.
Such a motor-powered seat adjustment device can be operated manually with the driver sitting on the seat. However, to make the seat position adjustment more convenient, an automatic seat position adjusting device has been proposed which can return the seat to an originally adjusted position.
Therefore, when the driver desires to return the seat position to an originally adjusted position after the driver himself or another driver has readjusted the seat position to suit his driving posture by means of a motor driving manual switch, a return switch on an operation panel located on a side of the seat may be operated. This causes originally adjusted position data stored in a memory at a time when a memory switch on the operation panel is operated to be fed into comparators where the stored position data are compared with the readjusted position data from each position sensor. The result of the comparison is fed into a control circuit which controls a driving circuit so as to make the readjusted position data equal to the originally adjusted position data. Consequently, the driving circuit drives a motor so as to return the changed seat position to the original position automatically. Such a motor-powered seat adjustment device described above has an adjustment mechanism for each of the seat direction adjustments so that the whole adjustment mechanism must be integrally built in a limited space within the seat.
In addition, the position sensors each comprising, e.g., limit switches and a gear mechanism the number of which correspond to the number of the seat member directions to be adjusted, must be included in the motor-powered seat adjustment device.
Therefore, there arises a problem that it is considerably difficult to incorporate such a number of position sensors into such a limited space wherein the driving motor or other adjustment mechanism are already incorporated. Further, a major change of the internal adjustment mechanism of the motor-powered seat would be involved.